Wall insert electric heater



July 9, 1929. H. A. MULVANY WALL INSERT ELECTRIC HEATER Filed B 1927 2 Sheets-Sheet 1 Ills lll l v (Q ill m 1 5 nlllllllKl v'lllu Q MW INVENTOR.

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WALL INSERT ELECTRIC HEATER Filed Feb- 1927 2 Sheets-Sheet 2 v I N VEN TOR.

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Patented July 9, 1929.

UNITED s'ra'res ime ATENT OFFHGE.

HARRY A. MULVANY, OF BERKELEY, CALIFORNIA, ASSIGNOR TO ELECTRIC SALES SERVICE COMPANY, OF SAN FRANCISCO,

IEORNIA.

Application filed February This invention relates to electric heaters of the wall insert type such as employed for room heating and the like. I

The object of the present invention is to generally improve and simplify the construction and operation of electric heaters; to provide an electric heater which will not only serve the function of a radiant heater, but also that of heating and circulating air; to provide an electric heater which may be readily inserted in the wall of a building; to provide means for rigidly securing the heating elements and their supports with relation to the heater frame; and further to provide means whereby the heating elements and their supports may be efficiently insu lated to prevent conduction losses to the heater frame and casing and to reduce fire danger to a minimum.

One form which the heater may assume is shown by way of illustration in the ac companying drawings in which Fig. 1 is a perspective view of the electric heater.

Fig. 2 is a perspective view of one of the heating element supports, this view also showing the manner of applying the heat ing element.

Fig. 3 is a rear view of the heater, showing the insulating member removed.

Fig. 4 is a vertical central cross-section taken on line IVIVFig. 1..

Fig. 5 is a cross-section of the heater taken on line VV Fig. 1.

Referring to the drawings in detail and particularly Figs. 1, 3 and 4, it may be stated that the heater consists of three main parts, to wit, a wall insert box A, a frame or face plate B and a grille C. The wall insert box is nothing more or less than a square or rectangular-shaped box constructed of sheet iron or like material consisting of a back section 2, side and end sections 3 and 4, and a flange 5. The front face of the box is open and is adapted to receive the main frame or face plate B and the members carried. thereby. The wall insert box is secured in the wall of a building in the usual manner. For instance, by securing the flange 5 tothe studding of the wall structure. The main frame B is square or rectangular in shape as shown in Figs. 1 and 3. Its central portion is provided with square or rectangular'shaped opening D CALIFORNIA, A CORPORATION OF CALI- WALL INSERT ELECTRIC HEATER.

2, 1927. Serial N0. 165,257.

and it is also provided with upper and lower rows of slots such as indicated at 6 and 7, the'function of which will hereinafter be described. The main frame B serves a number of functions First-that of a support for the-heating elements, hereinafter to be referred to.

Secondlythat of a support for the insulation whereby conduction losses are reduced to a minimum.

Thirdthat of supporting a switch whereby the circuit through the heating elements is circulated.

F1 ourth that of supporting the grille 0,

Fifththat of forming a closure for the wall insert box A and at the same time to produce an ornamental effect. I The face plate B in the main frame is provided with inclined inwardly extending top and bottom flanges such as shown at 8 and 9. It is also provided with side flanges 10 and 11. The side flanges 10 and 11 are'disposed at substantial right angles to the face of the frame l3 and they are extended inwardly some distance so as to form guides and retaining members for the heating element supports, generally indicated at E; and also to form a support for an insulating plate, generally indicated at 31 (see Figs. eland 5).

The heating element supports are perhaps best illustrated in Figs. 1 and 2. They consist of rectangular-shaped blocks constructed of a refractory material and consisting of a back 14, a pair of head or end members 15 and a plurality of projecting interspaced ribs 16. These ribs are also interspaced with relation to the head members 15 and their upper and lower ends are provided with projecting lugs 17 which serve the function -of retaining the heating elements against displacement. The heating element supports or blocks shown in Fig. 2 do not form any part of this invention as they are fully described in my co-pending application entitled Heating element support, filed 12- 22-1926, Ser. No. 156,325. Suficeth to say, however, that a number of these blocks are placed side by side across the opening D in the main frame as shown in Figs. 1 and 3, there being four such blocks in thepresent instance and the blocks are of such a width that they will substantially fill the space between the side flanges 10 and 11, andas this is the case, the blocks or heating element supports will be secured against lateral movement. Means must also be employed for securing the blocks against endwise movement. The means illustrated in the pre it instance are a pair of bars 18. These bars are secured to the upper and lower ends of the side flanges 10 and 11 by means of screws 19, and the blocks are thus rigidly secured both against lateral and endwise movement with relation to the opening I) in the main frame or :Eace plate B. By referring to Fig. 4-, it will be noted that the head members 15 of the respective blocks rest on the inner ends of the top and bottom flanges 8 and 9, and that the ribs 16 project through the opening I). The heating element employed is preferably of the ribbon type and the ribbon, usually constructed of nichrome metal, is preferably wound in zigzag fashion between the ribs as shown in Fig. 2, and it is retained against displacement by the up'-' per and lower lugs 17, The side flanges l0 and 11 are slotted as indicated at 21-, and the slotted portions are covered by insulated blocks 22 which are secured to the side flanges 10 and 11 by means of screws 33. Each insulating block carries a terminal connector 24. The ends of the'nichrome ribbon are passed through the slots 21 and connected with the inner ends of the terminal screws while the outer ends of the terminal screws are connected with the circuit wires 25 and 26. These are in turn connected with a switch 27 in any ordinary manner, and the circuit through the heating elements will thus be closed or broken as desired.

The refractory material from which heating element supports or blocks E the are

constructed, is a fairly poor heat conductor,

but, even so, it is found that the blocks gradually assume a temperature substantially equal to that of the ribbon elements carried thereby. The temperature reached often approximates 1500 to 1600 degrees 1 and care must accordingly be taken to reduce conduction losses to a minimum the etiiciency oi the heater from a practical point of view depends upon the amount of heat transferred to the atmosphere of the room. Care must also be taken that too much heatis not radiated or conducted to the wall insert ca ing A as fire danger is encountered. To reduce the conduction and radiant losses from the-heating element supports or blocks E to a minimum, one or more layers of asbestosor the like is placed rearwardly on the blocks crosswise of the side flanges 10 and 11 as in dicated at 30, and on top thereof is placed a polished plate 31. The plate and the asbes tos insulating material is secured in position and. against displacement by a series of screws such as shown in 32 which extend in to the ends of the side flanges 10 and. 11,

ducted through the asbestos andthe plate 31. I 'Such heat as may be conducted thereto is,

however dissiiated as a space is left between the bottom of the wall insert box and the plate 31 which permits a continuous circulation of air. This air enters through the lower slots 7 in the direction of arrow a. This air passes upwardly and finally discharges through the upper slots 6 in the direction of the arrow 1'). The amount of air thus circulated is, however, comparative- 151 small as a fairly small portion ofthe heat liberated passes through the plate 31. The sides of the insert boX are similarly protected as the air entering the slots 7 will also rise upwardly through the end passages indicated at 35, this air also discharging through the upper slots 6. The main air circulation is obtained from the face of the heater. Thatis, air )asses between the grille and the heating elements in the direction of arrow 0 and as such circulation is continuous while the heater is in operation, great quantities'ot air is heated.

With the use of ribbon elements held by blocks or supports of the character described, it is possible to eliminate metallic reflectors and the like, as the ribs and surface of the blocks diiiuses the radiant energy. This is also important as the radiant energy does not become sufliciently concentrated so as to cause scorching or overheating of furniture and the like placed in the immediate vicinity as is usually the case where reflector types of heaters are employed. The present heater dii'luses the radiant energy in practically every direction and as such produces a beneficial effect, and at the same time resents a rather attractive glowing surflice. The heater accordingly serves the function of circulating and heating air, and also that oi projecting radiant energy. The entire construction is exceedingly simple and substantial. The grille indicated at C protects the heating elements and also prevents accident by too closean approach. The general construction is exceedingly simple and installation may be alteeted wherever an opening can be formed in the wall.

lVhile certain features of the present invention are more or less specifically described and indicated, I wish it understood that various changes may be resorted to within the scope of the appended claims. Similarly that the materials and finish of the several parts employed, may be such as the manufacturer may dictate or varying conditions or uses may demand.

Having thus described my invention, What I claim and desire to secure by Letters Patent is- 1. In a heater of the character described, a frame consisting of a plate forming the front of the heater and provided With a central opening, said plate being also provided at the top and bottom of the opening With inclined flanges, blocks abutting against the rear edges of the inclined flanges and adapted to support heating means, and resilient clamping strips carried by the said plate and extending across the same at the top and bottom of the opening thereof, and engaging the blocks at the top and bottom thereof.

2. In a heater of the character described, a frame consisting of a plate forming the front of the heater and provided with a central opening, said plate being also provided at the top and bottom of the opening with inclined flanges and having vertt cal flanges at the sides of the opening, blocks located between the side flanges and abutting against the inclined flanges, resilient clamping strips mounted on the side flanges and extending across the space between the same and engaging the blocks at the top and bottom thereof, and the rear plate also supported by the said side flanges and arranged at the back of the blocks and con fining-the same between the clamping strips and in abutting relation With the inclined flanges.

HARRY A. MULVANY. 

